Method and composition for rendering



United States Patent Ofiice Patented .Aug. L1, 1.959

METHoD AND oQMPoSIrEoNFoR RENDERING POLYAC-RYLONITRIILE READILY DYEABLE No Drawing. Application April 6, 1953 'SerialNo. 347,144

4 Claims. 01. 3-100 This invention relates to a readily dyeable composition of polyacrylonitrileorof copolymers containing at least'85 percent by weight of'acrylonitrile in the polymer molecule, to fibrous articles made from such compositions, and to a method of making such polymers readily dyeable. It relates asqwell to a method of dyeing such polymers.

It is known that polyacrylonitrileand copolymers .con- 'taining 85 percent or more of acrylonitrile can be spun to form useful fibers. It is also known that, when spun from organic solvents, they canonly .be dyed with great diflicultyunless the fibers have been stretched so little as'to have a low tenacity or unless the polymeric structure includes reactive groups to bind a limited class of dyes. It has been proposed, also, to blend such dye assistants as polyvinylpyridine with polyacrylonitrile, and'to dissolve and spin the mixture. Such additives make difiicult control of the spinning procedure and of the fiber properties, The polymeric acrylonitrile can be dissolvedin' and spun from aqueous solutions of various highly hydrated metal salts. When such saline solutions are extrudedthrough spinnerets intoaqueous coagulants, such as water, dilute'brines or dilute acids, there is formed a*-swollen"aquagel structure from which strong, useful fibers can be formed by a series of stretching, 'Washing'and"drying operations. When such fibers are dried, they-are'as'hydrophobic as the ones obtained from organic solutions of'the same polymers, and present the same difiiculties-when it-is desired to dye them. It has been proposed, however, to dye the fibers during the course of'their production, .usingpan aqueous dye bath, andgapplying'the' dye to the fiber While the latter is in the swollen aquagel condition, before it has been sub- ,jected to irreversible drying. The so-outlined procedure Ilias made possibl'e'better dyeing of acrylonitrile polymer 'fibers than has 'beenobtained with fibers of the same .p'olymers spun 'from organic solvents, Ibut ithas a serious disadvantage. "The textile industry prefers to purchase .fibers in an undyed condition so as tohave complete freedom 'of' choice as .to ,color and shade of .the manufactured' goods. If fibers can only be obtained in a ready-dyed state or in an.undyeable state, .the textile 'Iindustry' is understandablyreluctant.to use such fibers. It

thetdyeing ofstructuressuch as fibersand filmsof poly meric bodies containingv at least percent of-,acryloni trile in the polymer molecule. A related object is to provide a method'wherebysuchstructures, made by coagulation of aqueous saline solutions of the polymer, may be treated so as to be .dyeabler after they have been dried. A particular object is to providesueh polymeric articles and compositions which/can be .dyedt freadily. with any common dye. I v

The invention-is based on the discovery that readily dyeableoriented products ,may .be made from the defined high acrylonitrile polymersaby, incorporating in the-spun article during the coursesof its manufactureand before it is dried and reduced .to-its final dimensions, a particular type of dye assistant ,to be defined hereinafter, and subsequently freeing .the article'rfrom ;-the saline medium while leaving the assistant .in .the dried :product. By.-the reference to adding the assistant to the product during thecourse of its manufacture is-meant introduction of the assistant into .the coagulated and still swollen spun product, vbeforenorflafter partial orientation. The, invention is applicable to products made. by wet-spinning of aqueous saline solutionsof the-polymer.

According to. the present invention, a polymer containing .at least 85 ,percent-acrylonitrile .in the polymer molecule is spun from anaqueoussaline solution thereof into an.aqueo us coagulant, and the coagulated product is stretched to effect orientation and is washed in any conventionalmanner to extract saline constituents. The amount of stretching imparted-should :be sufiicient to give a product having .a yieldpoint, when dried, of at least 0.8 gram .per denier, .as less fully oriented products, those with yield points, near.0.6 gram perdenier or less, may be dyed relatively-easily. Either before or after the initial coagulation, and. .while the :product is stillan aquagel, .i.e., .before. ithas been dried irreversibly, and preferably after most of the inorganic salt has been removed, a water-solubledye assistant, of a type to be defined hereinafter, ,is applied to and absorbed .by the aquagel product in amount to represent at least 1.0- percent of the dry Weight of the polymeric product. There after, the product is dried, .whilestill retaining the dye .assistant. The product may ,then be packaged, stored,

and subjected to fabrication. steps, such as. carding, twisting, spooling ,and knitting. or weaving, if desired, before being dyed. ,Any common type of dye may be used, andthe dyeingprocednre may .be .one which needs, at most, only slight modification, fromthat recommended for use with that ,dye ,whenapplied to the fibers (Wool, cotton, silk,-.vis cosc,or.acetaterayon, or nylon for which the. dye is primarily intended. Many-of the-useful procedures are outlined hereinafter.

The dye assistants of thepresent invention are significantly water-soluble ,salts of a member of the group:

(a) polyalkyl'ene amines, (b) ,fatty acid amides of such amines, (c) N-alkyl and ,carboxyalkyl derivatives of such amines, '(d) tN-alkyl and carboxyalkyl derivatives of the fatty acid amides of such amines, and (a) .condensation products of 'aldehyd'es with such amines, in all ofwhichthe polyalkylene amine has a molecular weight of at least 200. The polyalkylene amines all contain secondary amine groups, and, with reference to such groups, they may be called polyalkylene imines. The salts are hydrohalides, alkyl acid sulfates or any other significantly water-soluble salts of the polyalkylene amines. The'alkylene groups in such amines may be the ethylene, propylene 'or'butylenemadicals. When the polyalkylene amines :have molecular weightsbelowQOO, their salts do not have the permanence required of a dye assistant .in the invention, and 'when their molecular weights are over about 15,000, their salts may have too little solubilityin water to be as useful as desired.

Examples of the dye assistants of the present invention, all of which are effective in the process, are:

(1) Polyethylene amine hydrochloride.

(2) Polypropylene amine hydrobromide.

(3) Polyethylene amine bis lauryl amide hydrochloride.

(4) Polyethylene amine tetrastearamide hydrochloride.

(5) Condensation product of (1) with alkyl halides or sodium chloroacetate.

(6) Condensation product of (3) with alkyl halides or sodium chloroacetate.

(7) Condensation product of (1) with formaldehyde. All of these compounds are salts of polyalkylene amines and will be referred to as such herein.

In the method of the invention as applied to salt spun fibers, the time actually required for the water-swollen fiber to absorb the dye assistant is very brief, and varies with the degree of swelling of the fiber, the concentration of the liquid from which the assistant is applied, and the temperature of application. In some instances, enough of the assistant has been absorbed by the swollen fibers in 2 seconds. No adverse effect is found when the fibrous aquagel'is soaked in the assistant for several days. The assistant may be usedat full strength or in aqueous solutions which may be of any desired or convenient concentration. Thus, solutions containing as little as 0.1 percent by weight of the assistant have been used successfully. The assistant or its solution should be at a pH from 1 to 7, and should preferably be at a pH below 6, when applied to fibers in the swollen aquagel condition. The time and temperature of treatment, and concentration of the treating liquid should be so correlated as to cause the fibers to absorb at least 1.0 percent of their dry weight of the assistant. Amounts of 2 to 15 percent are preferred, but amounts as high as 40 percent are unobjectionable, though such large amounts are considered uneconomical. The temperature of treatment may be any temperature at which the aquagel fibers exist and at which the assistant or its solution is liquid. It is conven ent to effect the treatment at room temperature or at temperatures up to about 100 C., but temperatures of 10 C. or lower may be used if desired.

The salts of polyalkylene amines are applied to the spun polyacrylonitrile, while the latter is in the aquagel condition, from aqueous solutions of at least 0.1 percent concentration (preferably 0.3 to 1 percent), under conditions of time and temperature such that the swollen fibers take up at least 1 percent of the assistant, based on the dry weight of the polymer in the fiber.

The importance of absorbing the dye assistant in the undried and still swollen form of the fiber is illustrated in the following table. One sample of the fiber was treated as an aquagel with the identified dye assistant until it had absorbed 1.0 percent of the fiber dry weight of that agent. Another sample was dried and then soaked in the same agent until it would remove 5.0 percent of its weight of the agent from the bath. Both fibers were boiled in identical baths of Xylene 'Milling Blue FF containing 2 percent of the dye, 10

percent of sodium sulfate, and 2 percent of acetic acid, all percentages being based on the dry weight of the fibers.

The assistants have a greater aflinity for the swollen aquagel than for their own aqueous solutions. Thus, when the aquagel is soaked in solutions of the assistants until equilibrium is reached, a 0.1 percent solution may leave about 1.5 percent of the assistant in the fiber and a 1.0 percent solution may leave as much as 10 percent of the assistant in the fiber, at room temperature. At a given concentration of the assistant in water, the amount which can be absorbed by the swollen fibers remains about constant for temperatures from 15 to 45 C., but a further increase in temperature to about C. results in nearly twice as much of the assistant becoming absorbed in the fiber. Satisfactory dyeing is obtained whenever the fiber has been treated to carry 1.0 percent or more of its dry weight of the assistant, and the heaviest dyeing is found with fibers which carry over 1.5 percent of the assistant. There is no advantage to be gained through using over 40 percent of the assistant on the fibers.

The dye assistants of the present invention, when absorbed as described on the aquagel fibers, have made the subsequently dried fibers dyeable, using common classes of dyes including direct cotton and azoic dyes; vats; soluble vats; acid, acid-mordant and basic dyes; and acetate dyes. The following is a list of representative dyes which have been applied successfully by the present method. So far as possible, the Colour Index number of the dye is given, or the number of the recognized foreign prototype (marked PR) of the American dye employed, as listed in various editions of the Yearbook of the American Association of Textile Chemists and Colorists. In those cases in which neither a Cl. nor a PR number is reported, the dye definitely belongs to the class with which it is reported.

(a) Direct cotton dyes: C.I.

Chlorantine Fast Brown CLL Chlorantine Fast Green 5BLL PR 470 Chlorantine Fast Red 7B 278 Pontamine Green GX Conc. 594 Calcomine Black EXN Conc 581 Niagara Blue N Erie Fast Scarlet 4BA 326 (b) Acid dyes:

Anthraquinone Green GN 1078 Anthraquinone Blue AB 1075 Sulfonine Brown 2R Sulfonine Yellow 26 642 Neutracyl Brown RD Xylene Milling Black 28 304 Xylene Milling Blue FF Xylene Fast Rubine 3GP PAT PR412 Calcocid Navy Blue R Conc 289 Calcocid Navy Fast Blue BL 833 Calcocid Milling Red 3R 275 Alizarine Levelling Blue 2R Amacid Azo Yellow G Extra 146 (c) Mordant-acid dyes:

Alizarine Light Green GS 1078 Brilliant Alizarine Sky Blue BS PAT 1088 (d) Basic dyes:

Brilliant Green Crystals 662 Du Pont Methylene Blue ZX 922 Rhodamine B Extra S 749 (e) Vat dyes:

Midland Vat Blue R Powder 1183 Sulfanthrene Brown G Paste PR 121 Sulfanthrene Black PG Dbl. Paste Sulfanthrene Blue 2B Dbl. Paste 1184 Sulfanthrene Red 3B Paste 1212 (f) Soluble vat dyes: Indigosol Green IB Powder (g) Acetate dyes:

Celliton Fast Brown 3RA Extra CF PR 230 Celliton Fast Rubine BA CF PR 238 (1) Direct cotton dyes:

Bath to fiber ratio,\40'-8'0 1' Dye to fiber ratio,.0.02-0.05:1- l Sodium sulfate to fiber, .10.15:1' Bath temperature, 100 C. Time, 1-1.5 hours 7 Rinse in distilled water and dry (2) Acid dyes:

Bath to fiber ratio,'30-40:1 Dye to fiber ratio, .02-.05:1 Sodium sulfate, .10-2051' I Acetic acid, .02-.05:1 (for milling dyes), or Sulfuric acid, .02.05:1 (for levelling dyes). Bath temperatures,.100 C. (boil). Rinse and dry Acetate dyes: Bath'to fiber ratio, 30-40:1 Dye to fiber ratio, 0.02-.O:1. Nonionic wetting agent, 0.1% or less; Bath temperature-,100 C.- (boil9f about 1 hour. Rinse and dry' I H (4) Soluble vat- (procedurefor- Indigosol Green IB) Y Dissolve dyestuff -in hot-watercontaining 1 g'ram per liter of sodium carbonate. A'dd 1 percent sodium hydrosulfite and 20-to 40- percent sodium sulfate. Enter goods at 40 0., heat within 30 minutes to 90 C. Hold near 90 C. for l 'h'our. Rinse.

Prepare. developing bath of 1 to" 2 percent each of ammonium thiocyanate and potassium dichrom'ate. Treat goods in this bath 30 minutes at 30 C. Add grams sulfuric acid per liter, heat within 30 minutes to 85 C. and hold at 85-90 C. for 30 minutes. Rinse thoroughly, neutralize with dilute (2 grams per liter) sodium carbonate, rinse again and scour. (5) Vat: Procedure varies with the dye employed. For a satisfactory procedure when using sulfanthrene vat dyes, see Example 6, below.

The following specific examples illustrate the practice of the invention:

Example 1 A length (9 grns.) of water-swollen, unstretched tow, formed by extrusion of an aqueous saline solution of polyacrylonitrile through a 10 mil, 300 hole metal spinneret into an aqueous coagulating bath, was washed thoroughly to remove salt. It was then allowed to stand in 500 mls. of a 0.4% solution of polyethylene amine tetrastearamide hydrochloride (M.W. of amine over 1800) held at pH 3 with HCl at 25 C. until the fibers had absorbed at least 1 percent of the assistant. The tow was removed from the impregnating solution, stretched to 10 times its original length in moist steam, blown in a stream of air, and then dried for 8 minutes at 150 C. under little or no tension. The fibers had a tenacity of over 2 grams per denier.

The dried, impregnated tow was immersed in an aqueous dye bath containing 4.0% Pontamine Green GX Cone. 125% (C1. 594) and 15.0% sodium sulfate, both percentages being based on the weight of the fiber. The dye bath to fiber ratio was 40 to 1. The dye bath was held at 100 C. for 1.5 hours at which time the dye bath was co'ni'pletely exhausted Thedyed -tow was removed, rinseiil 'thoroughly i11 distillecf w'ater, and dried at-100 Cf for 0.5 hour: The tow wasdyed a deep; level green.

Example 2 A polyacrylonitrile-tow' was spun and washed as in Example 1; The water swollen tow'was stretched to 6 times its len'gth -while immersed for 4.5 secondsin an 0.8% aqueous solution of polyethylene amine tetrasteararnidehydrochloride" (M.W. of' amine 1800) at (3. and held at pH 3r withiHCl. The impregnated tow was stretcheditm14.4etimes its original length, in wet steam, and was dried oni-steam rolls, blown in an air stream, and dried relaxedfor 8 minutes at 150 C. This process was carried out continuously. The tow contained 3.0% ofthe additive=" The tow was then dyed by the rocedure; of Example-1 After-'drying,the tow was dyed a deep, level green and" contained 1.5% by weight of dye.'-- The-tow dyedin -Exa'mples-l-and 2 had a light and cro'ck fastnessequal"to cotton whendyed with the same dye andusing the-same-procedure.

Example 3 A polyacrylonitrile tow Was spun and washed as in Example 1. This" tow'was then stretched, impregnated with 316% octyl polyethylene amine hydrochloride (M.W. of-am'ine about 650), and dried by the procedure of Example 2. The dried impregnated' tow was immersed in an aqueous dye bath' containing 2.0% Xylene Milling Blue PF, 10% sodium sulfate, and 3-5% of acetic acid, all percentages being based on' the weight of the fibers. Thedyebath to fiber-ratio was 40-1. The dye bath was 'held'fat C. for one hour after'whichv'the tow was thoroughly rinsed, and dried at; C. for 10 minute's. The'tow was scoured. with a.0.5% solution of a nonion'ic detergentTat 60C. for 15"minutes. The tow was dyed alevel=blue.=

I Examp'le' l A polyacrylonitr'il'e tow wass u'n. and washed as in Example; -1 Tliis tow wasthen stretched, impregnated with the Hydrochloride of the condensation product of polyethylene amine (M.W. 5000) and sodium chloroacetate, and dried by the procedure of Example 2. The dried impregnated tow was immersed in an aqueous dye bath containing 2% Acetamine Yellow CG and 0.1% of a nonionic wetting agent, both percentages being based on the weight of the fibers. The dye bath to fiber ratio was 30-1. The dye bath was held at 100 C. for 1.5 hours, after which the tow was thoroughly rinsed and scoured with a 0.5% solution of a nonionic detergent at 60 C. for 15 minutes. A level yellow dyeing was obtained.

Example 5 A polyacrylonitrile tow was spun and washed as in Example 1. This tow was then stretched, impregnated with the hydrochloride of the his lauryl amide of polyethylene amine (M.W. of amine over 600), and dried by the procedure of Example 2. The dye bath was prepared by dissolving 2% Indigosol Green IB in hot water containing 1 gram per liter Na CO One percent sodium hydrosulfite and twenty percent sodium sulfate were added. The tow was entered at 40 C. and heated within /2 hour to 90 C., then treated for 1 hour at 90-95 C. and finally rinsed. The dye bath to fiber ratio was 20-1. The developing bath was prepared with 1% ammonium thiocyanate and 1% potassium dichromate dissolved in water and the tow was treated in this bath for /2 hour at 30 C. Ten grams of concentrated sulfuric acid per liter of bath was then added and the bath was heated within /2 hour to 85 C. The bath was then held for /2 hour at 8590 C. The tow was then rinsed thoroughly, neutralized with Na CO and rinsed again, The tow was dyed a level green.

,7 Example 6 A polyacrylonitrile tow was spun and washed as in Example 1. This tow was then stretched, impregnated with the hydrochloride of the reaction product of polyethylene amine (M.W. 1800) with 4 moles of formaldehyde, and dried by the procedure of Example 2. A dye bath was then prepared with 4% S'ulfanthrene Red 3B paste, sodium hydroxide, and 10% sodium hydrosulfite. The tow was entered into the dye bath at a ratio of 20-1. The bath was held at 100. C. for /2 hour after which the .tow was entered into an oxidizing bath of 4% hydrogen peroxide. .The tow was then rinsed with cold water, nentarliZed wtih Na CO and rinsed again and had a uniform red color.

Example 7 A polyacrylonitrile tow was spunand washed as in Example 1. This tow was then stretched, impregnated with the same assistant as in Example 6, and dried by the procedure of Example 2. The dried impregnated tow was immersed in an aqueous dye bath containing 3.0% Pontarnine GreenGX Conc. 125% and sodium sulfate. The dye bath to fiber ratio was 40-1. The dye bath was held at 100 C. for 1.5 hours, following which the tow was rinsed and dried for 10 minutes at 150 C. The tow was then immersed in a bathcontaining 2% potassium dichromate and 2% acetic acid. The bath to fiber ratio was 40-1. This bath was held at 60 C. for /2 hour following which the tow was rinsed and dried. The product was dyed a level green.

Example 8 8 sulfate. The bath-fiber ratio was 15:1. This bath was held at 95100 C. for /2 hour after which the tow was rinsed and dried. 'Ihetow was dyed a deep level red.

'Weclaim: 4

;1.;In a process in which a polymer containing at least percent of -acrylonitrile in the polymer molecule is spun froman aqueous saline solution thereof into an aqueous coagulant, the spun product is stretched to an extent suflicient to yield a dried product having a yield point ofat least 0.8 gram per denier, and the stretched product is substantially freed from saline constituents and dried .to destroy the aquagel condition, the improvement which consists in: applying to the product while still in the aquagel condition at least 1.0 percent of its dry weight of a watersoluble salt of an N-carboxyalkyl derivative of a polyethylene amine having a molecular weight of at least 200, drying the so-treated product irreversibly, and thereafter dyeing the product.

2. The method claimed in claim 1, wherein the polymer subjected to spinning is polyacrylonitrile.

3. The method claimed in claim 1, wherein the dye assistant is the hydrochloride of a carboxymethylated polyethylene amine.

4. A dyeable fiber of alinearpolymer containing at least 85 percent acrylonitrile in the polymer molecule, carrying uniformly distributed therethrough at least 1.0 percent of its dry Weight of a water-soluble salt of an N-carboxyalkyl derivative of a polyethylene amine having a molecular weight of at least 200.

References Cited in the file of this patent UNITED STATES PATENTS 1,985,248 Ellis Dec. 25, 1934 2,135,633 Bienert Nov. 8, 1938 2,347,508 Rugeley Apr. 25, 1944 2,376,891 Alles May 29, 1945 2,558,735. Cresswell July 3, 1951 FOREIGN PATENTS 361,362 Great Britain Nov. 16, 1931 613,817 Great Britain Dec. 3, 1948 613,818 Great Britain Dec. 3, 1948 

1. IN A PROCESS IN WHICH A POLYMER CONTAINING AT LEAST 85 PERCENT OF ACRYLONITRILE IN THE POLYMER MOLECULE IS SPUN FROM AN AQUEOUS SALINE SOLUTION THEREOF INTO AN AQUEOUS COAGULANT, THE SPUN PRODUCT IS STRETCHED TO AN EXTENT SUFFICIENT TO YIELD A DRIED PRODUCT HAVING A YIELD POINT OF AT LEAST 0.8 GRAM PER DENIER, AND THE STRETCHED PRODUCT IS SUBSTANTIALLY FREED FROM SALINE CONSTITUENTS AND DRIED TO DESTROY THE AQUAGEL CONDITION, THE IMPROVEMENT WHICH CONSISTS IN: APPLYING TO THE PRODUCT WHILE STILL IN THE AQUAGEL CONDITION AT LEAST 1.0 PERCENT OF ITS DRY WEIGHT OF A WATER-SOLUBLE SALT OF AN N-CARBOXYALKYL DERIVATIVE OF A POLYETHYLENE AMINE HAVING A MOLECULE WEIGHT OF A LEAST 200, DRYING THE SO-TREATED PRODUCT IRREVERSIBLY, AND THEREAFTER DYEING THE PRODUCT. 